JP2012163700A - Image forming device and fixing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly determine quality degradation of a fixing device due to a material of a pressure roller.SOLUTION: An image forming device 1 comprises: a fixing device 33 having a heating roller 33 and a pressure roller 55; a threshold reading part 101a; a pressure comparing part 101a; and a failure reporting part 103c. The fixing device 33 includes an IC chip 77 and a pressure sensor 75. The IC chip 77 stores a threshold of the pressure between the heating roller 53 and the pressure roller 55. The pressure sensor 75 detects pressure between the heating roller 53 and the pressure roller 55. A threshold value read part 101a reads the threshold of the pressure from the IC chip 77. The pressure comparing part 101b compares the threshold of the pressure with the pressure detected by the pressure sensor 75. The failure reporting part 101c reports a failure of the fixing device 33 in accordance with a result obtained by the pressure comparing part 101b.

Description

  The present invention relates to a fixing device and an image forming apparatus including the fixing device.

  2. Description of the Related Art An electrophotographic image forming apparatus such as a copying machine, a facsimile machine, or a multifunction machine includes a charger, an exposure device, a developing device, and a transfer device around a photosensitive drum. In such an image forming apparatus, the photosensitive drum is charged and further exposed to form an electrostatic latent image on the surface of the photosensitive drum. Thereafter, the electrostatic latent image is developed to form a toner image, and the toner image is further transferred onto a predetermined sheet.

  The image forming apparatus further includes a fixing device. The fixing device is a device for fixing a toner image on a sheet, and includes a heating roller and a pressure roller. The heating roller has a heating element inside. The pressure roller includes a roller shaft made of a metal material and an elastic member made of a rubber body or sponge body such as silicon or urethane provided around the roller shaft, and is arranged so as to contact the heating roller. The When the sheet on which the toner image is transferred is passed between the heating roller and the pressure roller, the toner image is fixed to the sheet by applying heat and pressure to the sheet.

  In such a fixing device, when the adjustment of the nip pressure of the pressure roller with respect to the heating roller is not appropriate, a paper jam and a fixing failure occur between the heating roller and the pressure roller. Therefore, conventionally, there has been proposed a control method for measuring the pressing force between the heating roller and the pressure roller and making the nip pressure between the heating roller and the pressing roller constant based on the measured pressing force. (For example, refer to Patent Document 1).

Japanese Patent Laid-Open No. 09-022206

  The nip pressure between the heating roller and the pressure roller changes as the pressure roller deteriorates over time. In order to prevent paper jams and fixing failures that occur between the heating roller and the pressure roller, it is necessary to manage the aging of the nip pressure due to such deterioration of the pressure roller and to reduce the quality of the fixing device. In addition, it is required to predict defects in advance.

  An object of the present invention is to appropriately determine a deterioration in the quality of the fixing device due to the material of the pressure roller.

Hereinafter, a plurality of modes will be described as means for solving the problems. These aspects can be arbitrarily combined as necessary.
An image forming apparatus according to an aspect of the present invention includes a fixing device, a threshold value reading unit, a pressure comparison unit, and an abnormality notification unit. The fixing device includes a heating roller having a heat generating portion and a pressure roller provided in contact with the heating roller. The fixing device further includes an IC chip that stores a threshold value of the pressure applied between the heating roller and the pressure roller, and a pressure sensor that detects the pressure applied between the heating roller and the pressure roller. The threshold value reading unit reads the pressure threshold value from the IC chip. The applied pressure comparison unit compares the applied pressure threshold value with the applied pressure detected by the pressure sensor. The abnormality notification unit notifies the abnormality of the fixing device according to the comparison result of the pressure comparison unit.

Here, the pressure threshold value between the heating roller and the pressure roller that guarantees the quality of the pressure roller is compared with the pressure detected by the pressure sensor, and according to the result of the comparison, the fixing device Abnormality can be reported. Therefore, for example, when the pressure applied between the heating roller and the pressure roller of the pressure roller changes below the threshold due to deterioration of the pressure roller, it is properly determined that the fixing device is abnormal. I can judge. In addition, when the abnormality of the fixing device is determined, the user can be notified of the abnormality of the fixing device, so that the user can replace the fixing device at an appropriate time.
Note that a value indicating the allowable limit of the quality of the pressure roller may be selected as the threshold value of the pressing force. Further, a different value is set as the threshold value of the pressure depending on the material of the pressure roller.

The fixing device may further include a housing that accommodates a heating roller, a pressure roller, and a pressure sensor. Here, the IC chip is provided in a portion of the housing on the pressure roller side.
Thus, by providing the IC chip in the vicinity of the pressure roller, it is possible to avoid the influence of the heat generated from the heating roller on the IC chip.

  A fixing device according to another aspect of the present invention may include a heating roller having a heat generating portion, a pressure roller provided in contact with the heating roller, an IC chip, and a pressure sensor. The IC chip stores a threshold value of the pressure between the heating roller and the pressure roller. The pressure sensor detects the pressure applied between the heating roller and the pressure roller.

  In the present invention, the deterioration of the quality of the fixing device due to the deterioration of the pressure roller is appropriately determined. Further, when the abnormality of the fixing device is determined, the user is notified of the abnormality of the fixing device, so that the user can replace the fixing device at an appropriate time.

1 is a schematic diagram of an entire image forming apparatus according to an embodiment of the present invention. 1 is a schematic perspective view of a fixing device. XX line enlarged schematic sectional drawing in FIG. FIG. 2 is a block diagram illustrating a main configuration of the image forming apparatus. The graph which shows the example of the relationship between the threshold value of a applied pressure, and the value of the applied pressure read from the pressure sensor. 6 is a flowchart for explaining a fixing device abnormality notification process by a CPU. FIG. 6 is an enlarged schematic cross-sectional view of a fixing device including a pressure sensor according to another embodiment.

1. First Embodiment (1) Structure of Image Forming Apparatus The image forming apparatus 1 will be described with reference to FIG. FIG. 1 is a schematic diagram of the entire image forming apparatus according to the present embodiment. Hereinafter, in order to clarify the directional relationship in the image forming apparatus 1, the directions for the worker standing on the front surface (front side in FIG. 1) of the image forming apparatus 1 are the left-right direction, the front-rear direction, and the up-down direction. .

The image forming apparatus 1 includes an image reading device 2 and an image forming device main body 3.
The image reading apparatus 2 includes an image reading unit 21 and a document cover 22. The image reading unit 21 is a device that reads image data of a document, and is a so-called flatbed scanner. The image reading unit 21 includes a light source 23, a plurality of reflecting mirrors 24, and a scanner unit 25. In the image reading unit 21, the light irradiated and reflected from the light source 23 onto the original on the platen glass 26 is guided to the scanner unit 25 while being reflected by the plurality of reflecting mirrors 24. The document cover 22 is rotatably disposed on the image reading unit 21.

  The image forming apparatus main body 3 includes a housing 31, and an image forming unit 32, a fixing device 33, a paper transport unit 34, a paper feed cassette 35, a manual paper feed tray 36, and paper discharge provided inside the housing 31. Part 37.

  The image forming unit 32 forms an image on the sheet 7 based on the original image data read by the image reading device 2 and the image data sent from the personal computer. The image forming unit 32 includes a photosensitive drum 40, a charger 41, an exposure head 42, a developing device 43, a transfer roller 44, and the like.

  The photosensitive drum 40 is a device that forms an electrostatic latent image on the surface. The photosensitive drum 40 is a columnar member that is rotatably provided. The photosensitive drum 40 is rotated counterclockwise in FIG. 1 about a rotation axis perpendicular to the paper surface direction of FIG. 1 by a driving device (not shown). The charging device 41, the exposure head 42, the developing device 43, and the transfer roller 44 are provided in this order in the rotation direction of the photosensitive drum 40.

The charger 41 uniformly charges the surface of the photosensitive drum 40 to a predetermined potential.
The exposure head 42 draws an electrostatic latent image along the image data by irradiating the surface of the charged photosensitive drum 40 with light. The exposure head 42 includes, for example, an LED (Light Emitting Diode) as a light source.

  The developing device 43 supplies toner to the electrostatic latent image on the photosensitive drum 40 and develops the electrostatic latent image. In the developing device 43, a predetermined potential is applied to the toner. Based on the difference between the potential and the potential of the electrostatic latent image, toner is attached to the electrostatic latent image, and the electrostatic latent image is visualized.

  The fixing device 33 fixes the toner image on the paper 7 by applying heat and pressure to the paper 7 after the transfer. Details of the fixing device 33 will be described later.

  The paper transport unit 34 includes a plurality of rollers including a transport path P1 and a registration roller pair 39. The paper transport unit 34 transports the paper 7 along the transport path by a roller, so that a paper discharge unit passes through the image forming unit 32 and the fixing device 33 from a paper feed cassette 35 or a manual paper feed tray 36 to be described later. The sheet 7 is conveyed up to 37.

The sheet feeding cassette 35 accommodates a bundle of sheets 7 before image formation. The paper feed cassette 35 is provided so as to be able to be taken in and out of the housing 31.
The manual paper feed tray 36 has a manual paper feed function for special paper such as postcards.
The paper discharge unit 37 is a part for discharging the paper 7 on which the image is formed. The paper discharge unit 37 is provided on the downstream side of the fixing device 33, and includes a discharge roller pair 37a and a discharge tray 37b.

  The image forming apparatus 1 of the present embodiment has a double-sided recording function, and a reverse conveyance path P2 that joins the conveyance path P1 is formed on the upstream side of the registration roller pair 39. A plurality of rollers including a pair of conveyance rollers 45 are provided in the reverse conveyance path P2. In the case of duplex recording, the sheet 7 on which single-sided recording is performed is transported along the transport path P1, and when the trailing edge of the sheet reaches the discharge roller pair 37a, the discharge roller pair 37a temporarily stops and the trailing edge of the sheet 7 is stopped. Nip. Next, the discharge roller pair 37a rotates in the reverse direction, and the sheet 7 is conveyed from the rear end to the reverse conveyance path P2 by the conveyance roller pair 45, and then joins the conveyance path P1 to reach the registration roller pair 39.

(2) Structure of Fixing Device The fixing device 33 will be described with reference to FIGS. FIG. 2 is a schematic perspective view of the fixing device. FIG. 3 is an enlarged schematic cross-sectional view taken along the line XX in FIG. The fixing device 33 is a device for fixing the toner image on the paper 7 by applying heat and pressure to the paper 7 after the transfer as described above, and is detachably attached to the image forming apparatus 1.

The fixing device 33 includes a heating roller 53, a pressure roller 55, a tension spring 61, a bracket 63, and a cleaning roller 59 in a fixing device housing 51 molded of resin. The fixing device 33 further includes a nip release mechanism 57, a casing 71, a sensor support member 73, a pressure sensor 75, and an IC chip 77.
In the present embodiment, one first roller 45 a of the pair of transport rollers 45 described above is disposed on the right side surface of the fixing device 33. The other second roller is disposed on the image forming apparatus main body 3 side so as to face one first roller 45a.

The fixing device housing 51 is provided with a lower opening 51a, an upper first opening 51b, a peeling claw 51c, a first guide rib 51d, a second guide rib 51e, and an upper second opening 51f.
The lower opening 51a is provided below the fixing device housing 51, and receives the sheet 7 conveyed along the conveyance path P1. The upper second opening 51 b is provided above the fixing device housing 51 and discharges the paper 7 on which the toner image is fixed toward the paper discharge unit 37.

The peeling claw 51 c is provided at the left edge of the upper first opening 51 b and peels off the paper 7 conveyed along the outer peripheral surface of the heating roller 53. The peeling claw 51c is configured to be swingable with respect to the fixing device housing 51, and is always urged by a torsion spring (not shown) or the like so that the tip of the heating claw 53 comes into contact with the outer peripheral surface.
A plurality of first guide ribs 51 d are provided along the left edge of the upper first opening 51 b to guide the paper 7.

A plurality of second guide ribs 51 e are provided so as to protrude from the side surface of the fixing device 33 on the reverse conveyance path P <b> 2 side and guide the paper 7. Note that a plurality of guide ribs (not shown) protrude from the image forming apparatus main body 3 side facing the second guide rib 51e, and a gap formed between the second guide rib 51e and the reverse guide path P2 is formed between them. Part of it.
The upper second opening 51f is provided on the upper side of the fixing device housing 51 on the front and rear sides of the upper first opening 51b. A nip release lever 69 and a cam follower 65, which will be described later, are exposed from the upper second opening 51f.

  The heating roller 53 is formed hollow with a metal such as aluminum. The hollow portion of the heating roller 53 is provided with a halogen lamp or the like as a heat source, and energization of the halogen lamp is controlled so that the outer peripheral surface is maintained at a predetermined fixing temperature. The heating roller 53 is driven to rotate by a motor (not shown).

The pressure roller 55 includes a metal roller shaft 55a and an elastic member 55b provided around the metal roller shaft 55a. The elastic member 55b is formed of a rubber body such as urethane or a sponge body. The pressure roller 55 is rotatably supported by a bracket 63 (described later) that is rotated by the biasing force of the tension spring 61, and rotates according to the rotation of the heating roller 53.
The nip portion N is formed by urging the pressure roller 55 against the heating roller 53 by the urging force of the tension spring 61. Then, while the sheet 7 passes through the nip N between the heating roller 53 and the pressure roller 55, heat and pressure are applied to the sheet 7, and the toner image is fixed on the sheet 7.

The cleaning roller 59 removes paper dust and toner adhering to the surface of the heating roller 53.
As described above, the tension spring 61 is a biasing member that biases the pressure roller 55 against the heating roller 53. A first end of the tension spring 61 is wound and fixed on a protrusion 71 a protruding from the side wall of the casing 71, and a second end is connected to the bracket 63.

  The brackets 63 are formed in a substantially triangular shape from a rigid material such as metal, and are disposed at both front and rear end portions with the pressure roller 55 interposed therebetween. A roller bearing portion 63 a that supports the rotation of the roller shaft 55 a of the pressure roller 55 is provided at the approximate center of the bracket 63. The roller bearing portion 63a is formed with a through hole H for allowing the roller shaft 55a to pass therethrough. The through hole H of the present embodiment has a long hole shape extending in the left-right direction. Thus, since the through hole H has a long hole shape, a predetermined gap (play) is formed between the roller shaft 55a of the pressure roller 55 and the roller bearing portion 63a.

  The bracket 63 is further formed with a bracket bearing portion 63b and a spring receiving portion 63c. The bracket bearing portion 63b is supported by a bracket shaft 71b formed below a casing 71 described later so that the bracket 63 is rotated. The spring receiving portion 63 c is provided above the bracket 63 and is connected to the second end of the tension spring 61.

  With the above-described configuration, the bracket 63 is urged counterclockwise by the tension spring 61 with the bracket shaft 71b as a fulcrum when the heating roller 53 and the pressure roller 55 are in the nip state. As a result, the pressure roller 55 supported by the roller bearing portion 63 a is brought into contact with the heating roller 53.

  A nip releasing mechanism 57 is further provided at both front and rear end portions sandwiching the pressure roller 55. The nip releasing mechanism 57 is a mechanism for releasing the nip between the heating roller 53 and the pressure roller 55, and is provided with a cam follower 65 provided on the right end side of the bracket 63, a cam portion 67 acting on the cam follower 65, and a nip releasing lever. 69.

  The cam follower 65 is plate-shaped and is provided at the right end portion of the bracket 63 to constitute a cam contact surface with which the cam portion 67 contacts. The cam follower 65 is formed with a recess 65a into which a part of the cam portion 67 is inserted while the nip between the heating roller 53 and the pressure roller 55 is released.

The cam portion 67 is formed with a lever bearing portion 67 a that is rotatably supported by a lever shaft 71 c provided in the casing 71. The cam portion 67 has a standby surface 67b that is the right side surface of the cam portion 67 and constitutes the basic radius of the cam, an action surface 67c that constitutes the outer radius of the cam, and a start end portion 67d and a termination portion 67e of the action surface 67c. .
The nip release lever 69 is formed integrally with the cam portion 67 and is made of hard resin or the like. The nip release lever 69 includes a first lever portion 69a connected to the terminal end portion 67e of the working surface 67c, and a second lever portion 69b connected to be bent with respect to the first lever portion 69a. The nip release lever 69 separates the pressure roller 55 from the heating roller 53 by causing the cam portion 67 to act on the cam follower 65 against the urging force of the tension spring 61.
The cam follower 65 and the nip release lever 69 are partly exposed from the upper second opening 51 f formed in the fixing device housing 51, and are arranged so that the nip release lever 69 can be operated from the outside of the fixing device 33. .

  When releasing the nip from the nip state between the heating roller 53 and the pressure roller 55, the nip release lever 69 is rotated clockwise about the lever shaft 71c. Thereby, the start end portion 67d of the working surface 67c of the cam portion 67 contacts the cam follower 65, and the bracket 63 is rotated clockwise around the bracket shaft 71b. With the rotation of the bracket 63, the pressure roller 55 supported by the roller bearing portion 63a of the bracket 63 is separated from the heating roller 53, and the nip is released.

  Further, in order to change from the state where the nip between the heating roller 53 and the pressure roller 55 is released to the nip state, the nip release lever 69 is rotated counterclockwise. By this rotation, the contact between the cam portion 67 and the cam follower 65 is released, and the bracket 63 is biased by the tension spring 61. As a result, the bracket 63 rotates counterclockwise with the bracket shaft 71b as a fulcrum, and the pressure roller 55 supported by the roller bearing portion 63a comes into contact with the heating roller 53 to be in a nip state.

The sensor support member 73 is a plate-like member that supports the pressure sensor 75, and is fixedly disposed on the bracket 63. Specifically, it is disposed at a position where the pressure sensor 75 can contact the roller bearing portion 63 a on the bracket 63.
The pressure sensor 75 is supported by the sensor support member 73 and contacts the roller bearing portion 63a to detect the pressure applied between the heating roller 53 and the pressure roller 55. The pressure sensor 75 is a strain gauge, for example. The pressure value detected by the pressure sensor 75 is read by the CPU 101 via the sensor output processing circuit 81 at predetermined intervals (see FIG. 4). In the present embodiment, the signal indicating the value of the applied pressure is a digital signal.

As shown in FIG. 2, the IC chip 77 is provided on the fixing device housing 51 and in the vicinity of the pressure roller 55. By providing the IC chip 77 in the vicinity of the pressure roller 55, the influence of heat generated from the heating roller 53 on the IC chip 77 can be reduced.
The IC chip 77 includes a storage unit that stores threshold data of pressure applied by the pressure roller 55 and a communication control unit that transmits the stored threshold data to the CPU 101.

  The threshold data of the pressing force is a value of the pressing force for guaranteeing the quality of the pressure roller 55 and operating the fixing device 33 normally. In other words, the threshold data has a value indicating the allowable limit of the quality of the pressure roller 55. The applied pressure between the heating roller 53 and the pressure roller 55 changes with time depending on the material of the pressure roller 55, and when the pressure is less than a predetermined value, the nip force between the heating roller 53 and the pressure roller 55 Is insufficient. Insufficient nip force causes poor fixing in the fixing device 33 or a paper jam between the heating roller 53 and the pressure roller 55. Therefore, before the fixing device 33 is shipped, a value corresponding to the material of the pressure roller 55 is stored in the IC chip 77 as threshold value data of the pressing force.

(3) Configuration of Control System of Image Forming Apparatus The configuration of the control system of the image forming apparatus 1 will be described with reference to FIG. FIG. 4 is a block diagram illustrating a main configuration of the image forming apparatus.

As shown in FIG. 4, the image forming apparatus 1 is a so-called multi-function machine having functions as a copier, a printer, a scanner, a facsimile machine, and the like. In addition to the configuration described above, the image forming apparatus 1 includes a CPU 101, a ROM 103, a RAM 105, a CODEC 107, an image memory 109, a modem 111, and an NCU 113. The image forming apparatus 1 further includes a scanner controller 115, a printer controller 117, an operation panel 119, a network board 121, and a timer 123.
Further, the image forming apparatus 1 includes a bus 125, and each unit in the image forming apparatus 1 is connected to each other via the bus 125.

  A CPU (Central Processing Unit) 101 is a control unit that controls each unit of the image forming apparatus 1. The CPU 101 implements a copy function, a printer function, a facsimile function, a scan function, and the like by reading and executing various programs stored in the ROM 103.

The CPU 101 of the present embodiment further includes a threshold value reading unit 101a, a pressure comparison unit 101b, and an abnormality notification unit 101c.
The threshold value reading unit 101 a reads the threshold value of the pressing force of the pressure roller 55 stored in the IC chip 77. Then, the read threshold value of the applied pressure is stored in the RAM 105. The CPU 101 and the IC chip 77 are connected by a serial bus 127. In this case, the CPU 101 and the IC chip 77 may be connected by a contact electrode or a harness. On the other hand, the CPU 101 and the IC chip 77 may be connected by a parallel bus.

  The pressure comparison unit 101b reads the pressure value between the heating roller 53 and the pressure roller 55 detected by the pressure sensor 75 at a predetermined interval via the sensor output processing circuit 81, and reads the pressure value thus read. And the threshold value of the pressurizing force stored in the RAM 105 are compared. When the read pressure value is smaller than the pressure threshold value, the pressure comparison unit 101b determines that the fixing device 33 is in an abnormal state and outputs an abnormality signal to the abnormality notification unit 101c.

With reference to FIG. 5, the relationship between the pressure threshold value stored in the RAM 105 and the pressure value read from the pressure sensor 75 will be described. FIG. 5 is a graph showing an example of the relationship between the pressure threshold and the pressure value read from the pressure sensor. In FIG. 5, the case where the material of the elastic member 55b of a pressure roller is A and the case where it is B are mentioned as an example.
When the material of the elastic member 55b of the pressure roller is A, when the value of the pressure applied to the pressure roller 55 is larger than the threshold A (0 <T ≦ Ta), the pressure roller 55 Therefore, it is determined that the fixing device 33 operates normally. On the other hand, when the pressure applied by the pressure roller 55 is smaller than the threshold A (Ta <T), it is determined that the pressure roller 55 and thus the fixing device 33 is abnormal.
Similarly, when the material of the elastic member 55b of the pressure roller 55 is B, the pressure applied to the pressure roller 55 detected from the threshold value B stored in the RAM 105 is large (0 <T ≦ Tb). ), The quality of the pressure roller 55 is guaranteed, that is, it is determined that the fixing device 33 operates normally. On the other hand, when the value of the pressing force of the pressure roller 55 is smaller than the threshold value B stored in the RAM 105 (Tb <T), it is determined that the pressure roller 55 and thus the fixing device 33 is abnormal.

  As a threshold value of the pressing force, a value of what percentage of the pressing force at the start of use of the pressure roller may be set regardless of the material of the pressure roller. That is, the pressure roller may be set to be determined to be in an abnormal state when the pressure applied to the pressure roller is reduced to what percentage. Different threshold values may be set according to the material of the pressure roller.

  The abnormality notifying unit 101c notifies the abnormality of the fixing device 33 when an abnormality signal is received from the pressure comparing unit 101b. Specifically, the abnormality notifying unit 101c notifies the user by displaying on the operation panel 119 a message indicating an abnormality of the fixing device 33 and prompting the user to replace the fixing device 33.

A ROM (Read Only Memory) 103 stores a control program, preset parameters, and the like. A RAM (Random Access Memory) 105 functions as a work area for executing a program.
A CODEC (Coder and Decoder) 107 compresses / decompresses image data. That is, the CODEC 107 compresses (encodes), for example, a JPEG image file, decodes a JPEG image file, decodes image data received by facsimile, and the like on the original image data received from the scanner controller 115. A known format can be adopted as the compression format.

The image memory 109 stores received data or image data read by the image reading device 2 (see FIG. 1).
The modem 111 is a modem device that mutually converts a digital signal and an analog signal, and is connected to the NCU 113.

An NCU (Network Control Unit) 113 is connected to a public switched telephone network (PSTN) and controls communication including outgoing and incoming calls via a telephone line.
The scanner controller 115 controls the operation of the image reading device 2 described above under the control of the CPU 101 and transmits the read image data to the image memory 109.

The printer controller 117 realizes an image forming function as a printer or a copier by controlling the operations of the image forming unit 32, the fixing device 33, the paper transport unit 34, and the like described above under the control of the CPU 101.
The operation panel 119 includes a touch panel having a display panel and a touch sensor, a hard key, and the like. The operation panel 119 displays an image on the display panel, thereby notifying the user of information such as the operation status of the image forming apparatus 1 and the occurrence of an error, and accepting an operation from the user via a soft key and a hard key. Can do. That is, the user can input an instruction such as copying, scanning, or facsimile transmission using the operation panel 119.

The network board 121 enables the image forming apparatus 1 to connect to the Internet and enables communication with other devices of the image forming apparatus 1.
The timer 123 operates regardless of the image forming processing operation of the image forming apparatus 1, and is constituted by a clock circuit, for example.

(4) Fixing Device Abnormality Notification Processing by CPU Next, the abnormality notification processing of the fixing device 33 by the CPU 101 will be described with reference to FIG. FIG. 6 is a flowchart for explaining the abnormality notification processing of the fixing device by the CPU.
First, the CPU 101 reads the pressure threshold value stored in the storage unit of the IC chip 77 from the IC chip 77 (step S11). For example, the CPU 101 reads the threshold value of the pressure from the IC chip 77 at the timing when the fixing device 33 is mounted on the image forming apparatus 1 due to shipment of the image forming apparatus 1 or replacement due to a malfunction of the fixing device 33. Next, the CPU 101 stores the read pressure force threshold in the RAM 105 (step S13).

  Thereafter, the CPU 101 reads the pressure value detected by the pressure sensor 75 at a predetermined interval, and compares the read pressure value with the pressure threshold value stored in the RAM 105 (steps S15 to S21). Specifically, the CPU 101 activates the timer 123 (step S15) and starts measuring a predetermined time. Next, the CPU 101 determines whether or not the timer 123 has expired (step S17). When the timer 123 has timed up (Yes in step S17), the CPU 101 reads the pressure value detected by the pressure sensor 75 (step S19). Thereafter, the CPU 101 compares the pressure value read from the pressure sensor 75 with the pressure value threshold value stored in the RAM 105 (step S21). When the pressure value read from the pressure sensor 75 is smaller than the pressure threshold value stored in the RAM 105 as a result of the comparison (Yes in step S23), the CPU 101 notifies the operation panel 119 of the abnormality of the fixing device 33. A message is displayed (step S23). For example, the CPU 101 displays a message notifying the replacement of the fixing device 33 on the operation panel 119 and prompts the user to replace the fixing device 33. If the pressure value read from the pressure sensor 75 is equal to or greater than the pressure threshold value stored in the RAM 105 as a result of the comparison (No in step S23), the CPU 101 returns to step S15.

  As described above, the CPU 101 can appropriately determine the abnormality of the fixing device 33 due to the deterioration of the pressure roller 55. As a result, problems that occur when the pressure between the heating roller 53 and the pressure roller 55 changes due to the deterioration of the pressure roller 55 are prevented. The defect in this case is a fixing failure in the fixing device 33 or a paper jam between the heating roller 53 and the pressure roller 55. Further, when an abnormality of the fixing device 33 is determined, since the abnormality of the fixing device 33 can be notified to the user, the user can replace the fixing device at an appropriate time.

(5) Features The above embodiment can be expressed as follows.
(A) The image forming apparatus 1 includes a fixing device 33, a threshold value reading unit 101a, a pressure comparison unit 101b, and an abnormality notification unit 103c. The fixing device 33 includes a heating roller 53 having a heat generating portion, a pressure roller 55 provided in contact with the heating roller 53, an IC chip 77, and a pressure sensor 75. The IC chip 77 stores a threshold value of pressure applied between the heating roller 53 and the pressure roller 55. The pressure sensor 75 detects the pressure applied between the heating roller 53 and the pressure roller 55. The threshold value reading unit 101 a reads the pressure value threshold value from the IC chip 77. The applied pressure comparison unit 101 b compares the applied pressure threshold value with the applied pressure detected by the pressure sensor 75. The abnormality notifying unit 101c notifies the abnormality of the fixing device 33 according to the comparison result of the pressure comparing unit 101b.
(B) The fixing device 33 further includes a fixing device housing 51 that houses the heating roller 53, the pressure roller 55, and the pressure sensor 75. Here, the IC chip 77 is provided on the pressure roller 55 side of the fixing device housing 51.

2. Other Embodiments Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. In particular, a plurality of embodiments and modifications described in this specification can be arbitrarily combined as necessary.

(A) In the above embodiment, the example in which the sensor support member 73 and the pressure sensor 75 are disposed only on the bracket 63 disposed on the front side (the near side in FIG. 3) has been described. However, the present invention is not limited to this example, and the sensor support member 73 and the pressure sensor 75 may be disposed on the rear bracket 63, or may be disposed on both sides of the front and rear brackets 63.
When the pressure sensors 75 are disposed on the front and rear brackets 63, the CPU 101 reads the pressure values from the two pressure sensors 75, and calculates the average value of the two read pressures. May be. Then, the CPU 101 may compare the pressure threshold value stored in the RAM 105 with the calculated average pressure value.

  (B) In the above embodiment, the pressure sensor 75 that is supported by the sensor support member 73 and that detects the pressure between the heating roller 53 and the pressure roller 55 in contact with the roller bearing portion 63a is taken as an example. . However, the pressure sensor is not limited to this example as long as the pressure applied between the heating roller 53 and the pressure roller 55 can be detected. For example, the pressure sensor 83 may be disposed at the position shown in FIG. FIG. 7 is an enlarged schematic cross-sectional view of a fixing device including a pressure sensor according to another embodiment. In FIG. 7, the configuration other than the arrangement of the pressure sensor 83 is the same as the configuration of the fixing device 33 shown in FIG. As shown in FIG. 7, the pressure sensor 83 is disposed on the heating roller 53 side. In this case, the pressure sensor 83 is supported by the casing 71 so as to be in direct contact with the heating roller 53.

  (C) In the above embodiment, the abnormality notifying unit 101 c has displayed an example of displaying a message indicating an abnormality of the fixing device 33 on the operation panel 119. However, the present invention is not limited to this example as long as the user can be notified of the abnormality of the fixing device 33. For example, the image forming apparatus 1 may further include a speaker, and notify the user of an abnormality in the fixing device 33 via the speaker. Further, an abnormality of the fixing device 33 may be notified to a user who uses another client terminal by transmitting an e-mail via the network board 121.

  (D) In the above embodiment, an example in which the CPU 101 and the IC chip 77 are connected by the serial bus 127 has been described. However, communication between the CPU 101 and the IC chip 77 is not limited to this example. For example, the CPU 101 and the IC chip 77 may communicate wirelessly (RF-ID, Radio Frequency Identification).

  (E) In the above embodiment, the signal indicating the pressure value detected by the pressure sensor 75 is an example of a digital signal. However, the signal indicating the pressure value may be an analog signal. In this case, the analog signal is input to the CPU 101 via the A / D port provided in the CPU 101.

  (F) In the above embodiment, the example in which the through hole H for penetrating the roller shaft 55a has a long hole shape has been described, but the present invention is not limited to this example. For example, the through hole H may be circular.

  The present invention can be widely applied to image forming apparatuses including a fixing device.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Image reading apparatus 3 Image forming apparatus main body 7 Paper 32 Image forming part 33 Fixing apparatus 34 Paper conveying part 35 Paper feed cassette 36 Manual paper feed tray 37 Paper discharge part 40 Photosensitive drum 51 Fixing device housing 51a Lower side Opening 51b Upper first opening 51c Peeling claw 51d First guide rib 51e Second guide rib 51f Upper second opening 53 Heating roller 55 Pressure roller 57 Nip releasing mechanism 59 Cleaning roller 61 Tension spring 63 Bracket 65 Cam follower 67 Cam part 69 Nip Release lever 71 Casing 73 Sensor support member 75 Pressure sensor 77 IC chip 81 Sensor output processing circuit 101 CPU
103 ROM
105 RAM
107 CODEC
109 Image memory 111 Modem 113 NCU
115 Scanner Controller 117 Printer Controller 119 Operation Panel 121 Network Board 123 Timer

Claims (3)

A heating roller having a heat generating portion; a pressure roller provided in contact with the heating roller; an IC chip for storing a threshold value of a pressure between the heating roller and the pressure roller; and the heating A fixing device having a pressure sensor for detecting pressure applied between the roller and the pressure roller;
A threshold value reading unit for reading the threshold value of the applied pressure from the IC chip;
A pressure comparison unit that compares the pressure threshold and the pressure detected by the pressure sensor;
An abnormality notifying unit for notifying the abnormality of the fixing device according to the comparison result of the pressing force comparing unit;
An image forming apparatus comprising: The fixing device further includes a housing that houses the heating roller, the pressure roller, and the pressure sensor,
The image forming apparatus according to claim 1, wherein the IC chip is provided in a portion of the housing on the pressure roller side. A heating roller having a heat generating part;
A pressure roller provided in contact with the heating roller;
An IC chip for storing a threshold value of the pressure between the heating roller and the pressure roller;
A pressure sensor for detecting a pressure applied between the heating roller and the pressure roller;
A fixing device.

Images